Furnace flue area reducing damper or baffle structure



May 22, 1956 u. N. KARJALA 2,746,406

FURNACE F LUE AREA REDUCING DAMPER OR BAFF'LE STRUCTURE Filed June 26, 1952 Ur/ro Niche/01' Karja/a INVENTOR.

Attorneys FURNACE FLUE AREA REDUCING DAMPER R V BAFFLE STRUCTURE Urho Nicholai Karjala, Cloquet, Minn. Application June 26, 1952, Serial No. 295,732 4 Claims. Cl. 110-97 i This invention relates in general to means for regulating the draft of flue gases, and more particularly to a damper adapted to be mounted within existing smoke pipes.

During the recentyears the prices of gas and oil suitable for burning in furnaces have been greatly reduced the type of system generally utilized with oil. Inasmuch as the air'for combustion is furnished by the blower, it is necessary that theflue be only suflicient to providea draft which will draw off the burnt gases, the gases already being under pressure. Therefore, when fluid fuels I are burnedin a solid fuel furnace, substantial and material changesmust be made in the flue and chimney system. It is, therefore desirable that a relatively simple and inexpensive device be provided which may be inserted in the portion of the flue and chimney system which would eliminate the substantial changes generallynecessary. I

The primary object of this invention is to provide an improved damper which may be quickly and conveniently positioned within a smoke pipe ofa converted furnace in order-tocont'rol theflow of gases through the flue and chimney system. i y

Another object of this invention is .to provide an improved damper which is provided with a bafile system, the baflle system reducing the effective area of the chimney system with which itis associated and at the same time preventing the passage of burning gases directly from the furnace into the chimney system. Another object of this invention is to provide an improved damperfor use with a smoke pipe of a converted furnace; said damper, being formed ofireadily obtainable sheet metal-products andbeihg .of a simple construction whereby it may beforrned in sheet metal fabricating shops at a minimum of expense so as to be economically feasible. 'A further object of this inventionis to provide an improved damper attachment for smoke pipes, said damper attachment being provided'with means for locking the same in a desired position with the smoke pipe.

With .these objects definitely in view, this invention resides in certain novel features of construction, combination and arrangement of elements and portions as will be hereinafter described in detail in the specification, particularly pointed out in the appended claims, and illustrated in the accompanying drawings which form a material part of this application and in which: V I p Figure 1 is a fragmentary elevational view of a portion of a converted furnace in the vicinity of its smoke pipe and the smokepipe being broken away and shown in sec- United State Parent ,4 Patented May, 22, 1956 ice damper positioned within the smoke pipe, the damper being shown in section in order to illustrate the construction thereof; and

Figure 2 is a transverse vertical sectional view taken substantially upon the plane indicated by the sectionline 2-2 of Figure 1 and shows the general outline of the damper and the construction of the baffles at one end thereof.

'Similar characters of reference designate similar or identical elements and portions throughout the specification and throughout the different views of the drawings. It will be understood that the furnace 28 on which the invention is installed is of a type which was initially designed for burning solid fuels, such as coal and wood, and that the same has been converted for burning a fluid fuel such as oil and that the same is provided with a blower (not shown) for blowing a desired quantity of air into the damper 33 Within the smoke pipe 26 adjacent its intersection with the furnace 28, the effective draft through the smoke pipe 26 is greatly reduced due to the provision of 1 the baflle plates 48 and 50. However, it will be understood that the sizes of the baffle plates 48 and 50 are such that suflicient area is left open to permit thepassage of the gases from the burning fuel. It will be understood that for different furnaces the desired opening will vary and accordingly, the baffle plates 48 and 50 may be made of different sizes for a certain diameter smoke pipe 26. It will be also understood that the damper 38 may be made of any diameter so as to be utilized with various diameter smoke pipes. Not only does the provision of the baflles 48 and 50 reduce the effective draft through the smoke pipe 26 but the tortuous passage required by the gases from the furnace 28 prevents the passage of burning gases 2 into the smoke pipe 26 which. would not only result in the inefficientoperation of the furnace 28, but also would possibly overheat the chimney system (not shown) associated with the smoke pipe 26.

Referring now to.Figures 1 and 2, it will be seen that there is illustrated the damper which may be mounted in the smokepipe 26 of the furnace 28, with the damper being referred to in general by the reference numeral 38. The damper 38 includes a sleeve, which is referred to in general by the referencenumeral 40, formed in two parts including an upper portion 42. and a lower portion 44 separated atone end by a gap 46. Secured to theupperportion 42 at one end thereof is, a first, bafile plate 48. Carried by the-lower portion 44 of thesleeve 40 is a second baflle plate 50 securedto the same intermediate its ends and extending upwardly into the upper portion 42. I

In order that the damper 33 may be secured within the smoke pipe 26, the same is provided with a pair of blocks 52 secured to the outer face of the baifle plate 48 adjacent a lower edge 54 thereof. Adjustably carried by the blocks 52 are downwardly and outwardly extending set screws 56. The set screws 56 are adapted to engage the inner surface of thesmoke' pipe 26 and force the upper portion 42 of the sleeve 40 into tight engagement therewith. It will be understood that the lower portion 44 rests upon the bottom of the smokepipe 26 in sealing relation. In order that the damper 38 may be conveniently positioned in and removed from the smoke pipe 26, the outer surface of the baflle plate 48 is provided with a handle 58.

In addition to the above recited elements, the damper lying the front face of the baffle plate 48 adjacent its in Figure 6, the transversely curved bafile plate 60 is generally rectangularin outline and extends forwardly and downwardly from the lower edge of thebaflle plate 48 with the lower edge thereof being positioned below the bottom of the sleeve 40 and the smoke pipe 26. Inasmuch as the damper 38 is positioned within the smoke pipe 26 adjacent its connection to the furnace 28, the forwardly extending transversely curved damper 60 is disposed within the furnace 28. i

The transversely curved bafile 60, being positioned adj acent one side of the furnace 28 and out of the general line of the burning fuel, gases entering the smoke pipe 26 are required to pass upwardly into the furnace 28 and down around the sides thereof and under the bafiie 60. Inasmuch'as the gases are circulated through the furnace 28 a maximum efliciency results and at the same time there is no possibility of burning gases entering the smoke pipe 26 through the damper 38. v r

The operation of this device will be understood from the foregoing description of the detailsthereof, taken in connection with the above recited objects anddrawings. Further description would appear to be unnecessary,

Minor modifications of the device, varying in minor details from the embodiment of the device illustrated and described here, may be resorted to without departing from the spirit and scope of this invention, as. defined in'the appended claims. l

Having described the invention, what is claimed as new is:

1. A damper adapted for use with a furnace converted to utilize a blower and having a smoke pipe, said damper comprising a sleeve adapted to be received in an intake.

end of the smoke pipe, said sleeve being provided with a bafile system for reducing the effective size of the smoke pipe, means for securing said damper within a smoke pipe, said battle system including a flat baflle at one end of said sleeve and closing the upper portion thereof, a transversely curved baffle secured adjacent to the lower end of said flat baffle and extending downwardly and outwardly beyond the sleeve in spaced relation'thereto for directing the flow of gases into a smoke pipe provided with the damper below said baffle.

2. A damper adapted for use with a furnace converted to utilize a blower and having a smoke pipe, said damper comprising a sleeve adapted to be received in an intake end of a smoke pipe, said sleeve being provided with a baffle system for reducing the effective size of the smoke pipe, means for securing said damper within a smoke pipe,

said baffle system including a flat baffle at one end of said sleeve and closing the upper portion thereof, a transversely curved baflle secured adjacent to the lower end of said flat battle, and extendingdownwardly and outwardly therefrom, said transversely curved baflle being generally rectangular in outline and extending outwardly lower edge 54 and welded thereto. As is best illustrated beyond and downwardly below the bottom of said sleeve in spaced relation for directing the flow of gases into a smoke pipe provided with the damper below said baffie.

3. A damper adapted for use with a furnace converted to utilize a blower and having a smoke pipe, said damper comprising a sleeve adapted to be received in a smoke pipe, said sleeve being providedwith a baflie system for reducing the efiective size of the smoke pipe, means for securing said damper with a smoke pipe, said bafiie system comprising a first bafile of less cross sectional area than the sleeve secured to said sleeve adjacent one end thereof, and leaving an open portion therethrough, a second baflle of less cross sectional area than the'sleeve secured within said sleeve intermediate its ends and leaving an open portion therethrough, said open portions of said sleeve adjacent said baffles being offset to form a tortuous passage, a transversely curved baflle secured to said first baflie adjacent the lower edge thereof and extending outwardly beyond and downwardly below the sleeve in spaced relation, said curved baffle being. curved transversely of its connection with said first baflle for directing gases into said sleeve below said first baffle.

4. A damper adapted for use with a furnace converted to utilize a blower and having a smoke pipe, said damper comprising a sleeve adapted to be'received in a smoke pipe, said sleeve being provided with a baffle system for reducing the effective size of the smoke pipe, means for securing said damper within a smoke pipe, said baflle system comprising a first bafile of less'crosssectional area than the sleeve secured to said sleeve adjacent one end thereof and leaving an open portion therethrough, a second battle of less cross sectional area than the sleeve secured within said sleeve intermediate'its ends and leaving an open portion therethrough, said open portions of said sleeve adjacent said baflles being offset to form a tortuous passage, a curved bafile secured to said first baflle adjacent the lower edge thereof and extending outwardly 3 beyond and downwardly below the sleeve in spaced relation, said curved baffle being curved transversely of its connection with said first baflle for. directing gases into said sleeve below said first baffle, said transversely curved baffle being generally rectangular in outline and extending outwardly beyond and downwardly below the bottom of said sleeve in spaced relation to the intake of the sleeve and smoke pipe.

' References Cited in the file of this patent UNITED STATES PATENTS 370,865 Hague Oct. 4, 1887 508,793 'Whitney Nov. 14, 1893 530,721 Ross Dec. 11, 1894 1,418,431 Damaska June 6, 1922 2,016,739 .Bouton Oct; 8, 1935 2,483,476 Ryden Oct. 4, 1949 v v FOREIGN PATENTS 78,284 Australia Sept. 25, 1919 507,981 France JulylO, 1920 

